Testing of cigarettes

ABSTRACT

A cigarette testing device comprises means to apply positive or negative pressure to one end of each cigarette; means defining a chamber around at least part of the cigarette, with seals around the cigarette to restrict communication between the interior of the chamber and atmosphere; and means to detect the pressure in the chamber during testing; and including means defining a predetermined deliberate leakage path between the chamber and atmosphere.

This invention is concerned with testing the wrappers of finishedcigarettes, especially filter-tipped cigarettes.

According to one aspect of this invention a cigarette testing devicecomprises means to apply positive or negative pressure to one end ofeach cigarette (i.e. to create a pressure inside the wrapper which isdifferent from atmospheric); means defining a chamber around at leastpart of the cigarette, with seals around the cigarette to restrictcommunication between the interior of the chamber and atmosphere; andmeans to detect the pressure in the chamber during testing; andincluding means defining a predetermined deliberate leakage path betweenthe chamber and atmosphere.

The predetermined leakage path may be at least partly through at leastone of the seals. In any event, the seals preferably have a clearancefit round the cigarette so as not to damage even the largest-diametercigarette which may occur within manufacturing tolerances for a givennominal diameter. Preferably the total leakage flow is substantiallygreater than the variation of leakage through the seals due to thevariations of cigarette diameter, so that the variable part of theleakage is swamped by the fixed part.

According to a second aspect of this invention, a cigarette testingdevice has a drum for carrying the cigarettes during testing, and anannular member which surrounds at least part of the drum and defineswith the drum an annular space around each cigarette at a testingstation, positive or negative pressure being supplied to the annularspace or sensed in the annular space to detect the presence of anexcessively leaking cigarette wrapping. Pressure may be supplied to oneend of the cigarette at the testing station, and the pressure in theannular space may be monitored; alternatively, pressure may be suppliedto the annular space, and the pressure may be monitored at one end ofthe cigarette.

The annular member may rotate about an axis parallel to the axis of thedrum, the annular member having an internal diameter which is largerthan the external diameter of the drum. Alternatively, the annularmember may be frusto-conical in shape, with an axis of rotation inclinedto that of the drum, so that the inside surface of the annular member isparallel to the outer surface of the drum at the testing station.

According to a third aspect of this invention, the wrapper of eachcigarette is tested while at least part of the cigarette lies within anaxial bore in a part of a testing drum, the bore having for example aninternal shape defining an annular space around the cigarette in whichthe pressure is monitored during testing. Each cigarette is blown intothe corresponding bore. For example, at least part of the length of thecigarette may be contained wholly within an axially extending flute inthe drum, aligned with a corresponding one of the bores, and at leastpart of each flute may be substantially closed by a cowl to define apassageway containing the cigarette into which compressed air is fed toblow the cigarette into the corresponding bore in preparation fortesting. Alternatively, each cigarette may be blown into the bore by anair jet issuing from a nozzle adjacent to one end of the cigarette, andthe reflected pressure of the air jet, or the noise generated by the airjet, may be detected as an indication of the condition of the cigaretteend, which in this case is preferably the tobacco-filled end; thedetection of the end quality in this respect is basically as describedin U.S. Pat. Nos. 3,720,311 or 3,483,970.

According to another aspect of this invention, each cigarette is carriedduring testing by a drum around part of which a belt extends, the belthaving integrally moulded portions at regular intervals defining withthe drum an annular space around each cigarette at a testing stationwhereby the cigarette is tested, for example by monitoring pressure inthe annular space or by supplying pressure to the annular space andmonitoring the pressure in an end space. The belt may have integrallymoulded timing teeth engaging the drum, or may alternatively have teethon the side remote from the drum and engaged by a drive gear.

Other aspects of this invention will become apparent from the followingdescription of various examples of devices according to this inventionshown in accompanying drawings. In the drawings:

FIG. 1 is a section in a plane passing through the axis of the testingdrum of one device;

FIG. 2 is a part of a similar section of a second device;

FIG. 3 is a fragmentary section in a plane normal to the axis of thetesting drum of a third device;

FIG. 4 is a section, similar to FIG. 1, of a fourth device;

FIG. 5 is a section, similar to FIG. 1, of a fifth device including aflexible belt;

FIG. 6 is an end view in the direction of the axis of the device shownin FIG. 5; and

FIG. 7 is an enlargement of part of part of FIG. 6.

FIG. 1 shows a cigarette 2 being tested while being carried by a testingdrum 4 which rotates about an axis 6. During testing, part of thecigarette (including the filter) extends into an axial bore orpassageway in a flange portion 4A of the drum. The internal wall of thebore includes a part 8 which fits closely around the end of thecigarette, a recessed part defining a large annular space 10, and aslightly recessed part defining an annular test space 12. Parts 14 and16 of the bore are a fairly close fit around the cigarette but allow apredetermined leakage from the annular space 12 to atmosphere; for thispurpose, and in order to ensure that the test space 12 is isolated fromthe pressure at the end of the cigarette, the annular space 10 is ventedto atmosphere through a passageway 11.

The annular space 12 contains the edge of the "cork" strip by which thefilter is joined to the tobacco-filled part of the cigarette, and theinterface between the tobacco and the filter. During testing, pressure(either positive or negative) is supplied to a fixed manifold 18,passing through a passage 18A in the manifold and into the adjacent endof the cigarette. The pressure in the annular test space 12 is monitoredby means of a transducer connected to a manifold 20 which communicateswith the test space 12 via a passageway 12A. An additional predeterminedleakage to atmosphere from the test space 12 may be provided by means ofa restricted passage to atmosphere extending from the passage 20A in themanifold.

Each cigarette is delivered on to the drum 4 with its left-hand endinitially at a position shown by the chain dotted line 22, at whichstage the cigarette is contained substantially entirely within a flutein part of the drum which is closely surrounded by a cowl 24 curvedabout the axis of the drum. The cigarette is then blown through theflute and into the bore in the part 4A of the drum by means ofcompressed air supplied through a passage 26A in a fixed member 26adjacent to the end of the drum. After testing, the cigarette ispreferably blown out of the bore by means of compressed air supplied tothe passage 18A. If the test is conducted by connecting positivepressure air to the manifold 18, the cigarette may be held against axialdisplacement out of the bore by means of suction applied through aradial passage 28 opening into the flute, or by means of an end stopwhich moves into the flute to about the left-hand end of the cigarette.

FIG. 2 shows a cigarette testing device including a drum 30 by which thecigarettes are carried during testing. The drum includes a flange 30Ahaving an axial passage 30B through which pressure is supplied to theadjacent end of the cigarette 32 at the testing station. A seal isformed in this instance by means of a conical seat 30C; the cigarette isblown against the conical seat but it may alternatively be suckedagainst the conical seat by means of suction applied to the passage 30B.The conical seat could alternatively be on a flexibly mounted member soas to be self aligning. An annular test space 34 is defined partly by aportion 30D of the drum 30 and partly by a second drum 36 which rotatesabout an axis parallel to that of the drum 30. The pressure in the testspace is monitored by means of a tranducer connected via a passageway36A in the drum 36, but may alternatively be monitored in the samemanner as in FIG. 1.

The cigarette is held on the testing drum until just before the testingstation by suction applied through a passage 38. Just before reachingthe testing station, the cigarette is displaced axially slightly intothe conical seat 30C by means of an air jet supplied through a pipe 40forming part of an end testing device such as that shown in either ofthe above-mentioned U.S. patent specifications. Preferably the wrappertest is conducted by transmitting suction through the passage 30B sothat the cigarette is held by the suction against the conical seat 30C,the air jet from the pipe 40 being terminated before the testingstation.

Instead of the conical seat 30C there may be a parallel-sided (i.e.cylindrical) recess or bore for receiving the end portion of thecigarette.

The two-drum arrangement shown in FIG. 2 may be modified in variousways. For example, the drum 36 may be extended to the right and mayco-operate with the drum 30 to form a seal around the right-hand end ofthe cigarette. Furthermore, the drums may be modified to define a testspace which extends further to the left, and possibly over substantiallythe whole length of the cigarette; however, the passage 36A leading tothe transducer or other sensing device preferably still leads into thetest space at the position shown, so as to provide maximum sensitivityto leaks in the region of the filter joint, the test space beingpossibly of such small radial extent as to produce a pressure drop alongthe test space, giving reduced sensitivity to leaks nearer the left-handend of the cigarette. The cooperating drums may in many respects besimilar to those of the cigarette inspection device described in ourBritish patent specification No. 1,217,203.

FIG. 3 shows an alternative way of defining a testing space around thecigarette by means of the drum carrying the cigarette, together with afurther rotary member. In this instance the cigarettes are carried by adrum 42, and the cooperating rotary member is an annular member 44 whichhas an internal diameter larger than the external diameter of the drum42 and and rotates about an axis parallel to, but displaced from, theaxis of the drum. The testing station is situated where the two membersare closest together; that is to say, the cigarette 46 is at the testingstation. The cigarettes are fed axially onto the drum 42 in a regionwhere the annular member 44 is well spaced from the drum; thisfacilitates the feed of the cigarettes onto the drum, since thecigarettes do not have to enter a close-fitting bore.

A longitudinal section through the cigarette 46 may be basically similarto the arrangement shown in FIG. 4. However, FIG. 4 shows an arrangementin which an annular member 48 of frusto-conical shape partly surrounds adrum 50, the axis of rotation 52 of the member 48 intersecting and beinginclined to the axis 54 of the drum. Thus the cigarettes can be fedtransversely on to the drum near the bottom of the drum where the member48 is clear of the drum. A cigarette 55 is shown at a testing station atwhich the drum and annular member 48 define between them a testing space56, a larger-diameter annular space 58 which is vented to atmosphere,and close fitting parts around the cigarette elsewhere. Pressure issupplied to the filter end of the cigarette through a passage 50A in thedrum, and the pressure in the test space 56 is monitored through apassage 56A.

FIGS. 5 to 7 show a further device which is similar to the device shownin FIG. 2 (as indicated by the use of the same reference numerals),except that the drum 36 in FIG. 2 is replaced by an endless belt 60. Asshown in FIG. 6, the belt 60 extends around part of the circumference ofthe drum 30 and passes around end pulleys 62 and 64. The external faceof the belt is moulded with projections 60A fitting closely round theouter halves of the cigarettes, and teeth 60B which engage in similarlyshaped grooves in the drum so that the belt is driven at the same speedas the drum and in a timed relationship. Near the smooth surface 60C ofthe belt there are longitudinally extending reinforcing wires 60D. Thebelt is moulded of a flexible plastics material.

As an alternative, the driving and timing teeth 60B may project from theface 60C of the belt, in which case one of the pulleys 62 or 64 may beformed as a gear to drive the belt.

Instead of the path of the belt being as shown in FIG. 6, the belt mayhang as an approximately oval loop from the drum, somewhat like theannular member 44 in FIG. 3, with a vertically movable pulley engagingor resting in the bottom of the loop to tension and/or possibly to drivethe belt.

In all the examples shown, the test is described in terms of supplyingpressure to the filter end of the cigarette and monitoring the pressurein a test space around the cigarette. As an alternative in each case,pressure could be supplied to the test space around the cigarette, andthe monitoring may be of pressure at the end of the cigarette,preferably with provision for a predetermined leakage path between theend space and atmosphere.

We claim:
 1. A cigarette testing device comprising means to applypressure difference from atmospheric pressure to one end of eachcigarette; means defining a chamber around at least part of thecigarette, with seals around the cigarette to restrict communicationbetween the interior of the chamber and atmosphere; and means to detectthe pressure in the chamber during testing; and including means defininga predetermined deliberate leakage path between the chamber andatmosphere.
 2. A cigarette testing device according to claim 1 in whichthe predetermined leakage path is at least partly through at least oneof the seals.
 3. A cigarette testing device comprising a drum forcarrying the cigarettes during testing, and an annular member whichsurrounds at least part of the drum and defines with the drum an annularspace around each cigarette at a testing station, positive or negativepressure being supplied to the annular space or sensed in the annularspace to detect the presence of an excessively leaking cigarettewrapping.
 4. A cigarette testing device according to claim 3 in whichthe annular member rotates about an axis parallel to the axis of thedrum, the annular member having an internal diameter which is largerthan the external diameter of the drum.
 5. A cigarette testing deviceaccording to claim 3 in which the annular member is frusto-conical inshape, with an axis of rotation inclined to that of the drum, so thatthe inside surface of the annular member is parallel to the outersurface of the drum at the testing station.
 6. A cigarette testingdevice according to claim 3 in which cigarettes are fed on to the drumat a position along its circumference where the annular member is spacedfrom the drum.
 7. A cigarette testing device according to claim 1 inwhich the wrapper of each cigarette is tested while at least part of thecigarette lies within an axial bore in part of a testing drum carryingthe cigarette, at least part of the length of each cigarette beingcontained wholly within an axially extending flute in the drum alignedwith a corresponding one of the bores, and at least part of the flutebeing substantially closed by a stationary cowl cooperating with theflute to define a passageway containing the cigarette into whichcompressed air is fed to blow the cigarette into the corresponding borein preparation for testing.